@inproceedings{SchmidtFanselowWirthetal., author = {Schmidt, Jochen and Fanselow, Stephanie and Wirth, Karl-Ernst and Peukert, Wolfgang and Hiller, Saskia and Laumer, Tobias and Schmidt, Michael}, title = {Herstellung von Polyolefinstrahlschmelzmaterialien mittels Schmelzeemulgieren zum Einsatz in der additiven Fertigung}, series = {Neue Entwicklungen in der Additiven Fertigung}, booktitle = {Neue Entwicklungen in der Additiven Fertigung}, editor = {Witt, Gerd and Wegner, Andreas and Sehrt, Jan}, publisher = {Springer}, address = {Berlin, Heidelberg}, isbn = {978-3-662-48472-2}, doi = {10.1007/978-3-662-48473-9_2}, pages = {13 -- 23}, abstract = {Im Rahmen dieses Beitrags wird das Schmelzeemulgieren als Verfahren zur Herstel-lung von Polymermikropartikeln vorgestellt. In diesem Prozess wird zun{\"a}chst ein Polymergranulat in einer kontinuierlichen Phase in Gegenwart geeigneter Additive in einem R{\"u}hrbeh{\"a}lter aufgeschmolzen, die Rohemulsion in einer Rotor-Stator-Einheit feinemulgiert und anschließend zu einer Suspension abgek{\"u}hlt. Der Einfluss von Prozessparametern und Systemzusam-mensetzung auf das Emulgierergebnis wird diskutiert und die Anwendbarkeit des Verfahrens f{\"u}r polymere Mikropartikeln anhand von Polypropylen (PP) und Polyethylen (PE-HD) dargestellt. Die erhaltenen Suspensionen werden zur {\"U}berf{\"u}hrung in Pulverform spr{\"u}hgetrocknet und die Fließeigenschaften des Pulvers analysiert. Durch trockenes Beschichten mit pyrogener Kiesels{\"a}ure kann die Fließf{\"a}higkeit der erhaltenen Partikeln weiter verbessert werden. Das Verfahren bietet somit einen neuen Zugang zur Herstellung neuer Ausgangsmaterialien f{\"u}r die Additive Fertigung.}, language = {de} } @article{BluemelSachsLaumeretal., author = {Bl{\"u}mel, Christina and Sachs, Marius and Laumer, Tobias and Winzer, Bettina and Schmidt, Jochen and Schmidt, Michael and Peukert, Wolfgang and Wirth, Karl-Ernst}, title = {Increasing flowability and bulk density of PE-HD powders by a dry particle coating process and impact on LBM processes}, series = {Rapid Prototyping Journal}, volume = {21}, journal = {Rapid Prototyping Journal}, number = {6}, publisher = {Emerald}, issn = {1758-7670}, doi = {10.1108/RPJ-07-2013-0074}, pages = {697 -- 704}, abstract = {Purpose - The purpose of this paper is to demonstrate the processability of cohesive PE-HD particles in laser beam melting processes (LBM) of polymers. Furthermore, we present a characterization method for polymer particles, which can predict the quality of the powder deposition via LBM processes. Design/methodology/approach - This study focuses on the application of dry particle coating processes to increase flowability and bulk density of PE-HD particles. Both has been measured and afterwards validated via powder deposition of PE-HD particles in a LBM machine. Findings - For efficient coating in a dry particle coating process, the PE-HD particles and the attached nanoparticles need to show similar surface chemistry, i.e. both need to behave either hydrophobic or hydrophilic. It is demonstrated that dry particle coating is appropriate to enhance flowability and bulk density of PE-HD particles and hence considerably improves LBM processes and the resulting product quality. Originality/value - At present, in LBM processes mainly polyamide (PA), 12 particles are used, which are so far quite expensive in comparison to, for example, PE-HD particles. This work provides a unique and versatile method for nanoparticulate surface modification which may be applied to a wide variety of materials. After the coating, the particles are applicable for the LBM process. Our results provide a correlation between flowability and bulk density and the resulting product quality.}, language = {en} } @misc{MauererRexhepajMonkmanetal., author = {Mauerer, Wolfgang and Rexhepaj, Tanja and Monkman, Gareth J. and Sindersberger, Dirk and Diermeier, Andreas and Neidhart, Thomas and Wolfrum, Dominik and Sterner, Michael and Heberl, Michael and Nusko, Robert and Maier, Georg and Nagl, Klaus and Reuter, Monika and Hofrichter, Andreas and Lex, Thomas and Lesch, Florian and Kieninger, B{\"a}rbel and Szalo, Alexander Eduard and Zehner, Alexander and Palm, Christoph and Joblin, Mitchell and Apel, Sven and Ramsauer, Ralf and Lohmann, Daniel and Westner, Markus and Strasser, Artur and Munndi, Maximilian and Ebner, Lena and Elsner, Michael and Weiß, Nils and Segerer, Matthias and Hackenberg, Rudolf and Steger, Sebastian and Schmailzl, Anton and Dostalek, Michael and Armbruster, Dominik and Koch, Fabian and Hierl, Stefan and Thumann, Philipp and Swidergal, Krzysztof and Wagner, Marcus and Briem, Ulrich and Diermeier, Andreas and Spreitzer, Stefan and Beiderbeck, Sabrina and Hook, Christian and Zobel, Martin and Weber, Tim and Groß, Simon and Penzkofer, Rainer and Dendorfer, Sebastian and Schillitz, Ingo and Bauer, Thomas and Rudolph, Clarissa and Schmidt, Katja and Liebetruth, Thomas and Hamer, Markus and Haug, Sonja and Vernim, Matthias and Weber, Karsten and Saßmannshausen, Sean Patrick and Books, Sebastian and Neuleitner, Nikolaus and Rechenauer, Christian and Steffens, Oliver and Kusterle, Wolfgang and G{\"o}mmel, Roland and Wellnitz, Felix and Stierstorfer, Johannes and Stadler, Dominik and Hofmann, Matthias J. and Motschmann, Hubert and Shamonin (Chamonine), Mikhail and Bleicher, Veronika and Fischer, Sebastian and Hackenberg, Rudolf and Horn, Anton and Kawasch, Raphael and Petzenhauser, Michael and Probst, Tobias and Udalzow, Anton and Dams, Florian and Schreiner, Rupert and Langer, Christoph and Prommesberger, Christian and Ławrowski, Robert Damian}, title = {Forschungsbericht 2016}, editor = {Baier, Wolfgang}, address = {Regensburg}, organization = {Ostbayerische Technische Hochschule Regensburg}, doi = {10.35096/othr/pub-1384}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:898-opus4-13840}, language = {de} } @misc{AppelhansKampmannMottoketal., author = {Appelhans, Marie-Luise and Kampmann, Matthias and Mottok, J{\"u}rgen and Riederer, Michael and Nagl, Klaus and Steffens, Oliver and D{\"u}nnweber, Jan and Wildgruber, Markus and Roth, Julius and Stadler, Timo and Palm, Christoph and Weiß, Martin Georg and Rochholz, Sandra and Bierl, Rudolf and Gschossmann, Andreas and Haug, Sonja and Schmidbauer, Simon and Koch, Anna and Westner, Markus and Bary, Benedikt von and Ellermeier, Andreas and V{\"o}gele, Daniel and Maiwald, Frederik and Hierl, Stefan and Schlamp, Matthias and Ehrlich, Ingo and Siegl, Marco and H{\"u}ntelmann, Sven and Wildfeuer, Matthias and Br{\"u}ckl, Oliver and Sterner, Michael and Hofrichter, Andreas and Eckert, Fabian and Bauer, Franz and Dawoud, Belal and Rabl, Hans-Peter and Gamisch, Bernd and Schmidt, Ottfried and Heberl, Michael and Thema, Martin and Mayer, Ulrike and Eller, Johannes and Sippenauer, Thomas and Adelt, Christian and Haslbeck, Matthias and Vogl, Bettina and Mauerer, Wolfgang and Ramsauer, Ralf and Lohmann, Daniel and Sax, Irmengard and Gabor, Thomas and Feld, Sebastian and Linnhoff-Popien, Claudia and Ławrowski, Robert Damian and Langer, Christoph and Schreiner, Rupert and Sellmair, Josef}, title = {Forschung 2019}, editor = {Baier, Wolfgang}, address = {Regensburg}, organization = {Ostbayerische Technische Hochschule Regensburg}, isbn = {978-3-9818209-7-3}, doi = {10.35096/othr/pub-789}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:898-opus4-7890}, pages = {72}, abstract = {Bericht mit Forschungsprojekten aus verschiedenen Bereichen der OTH Regensburg mit dem Schwerpunktthema "K{\"u}nstliche Intelligenz" und einem Gespr{\"a}ch zur "Medizin der Zukunft"}, subject = {Forschung}, language = {de} } @misc{BroserFalterŁawrowskietal., author = {Broser, Christian and Falter, Thomas and Ławrowski, Robert Damian and Altenbuchner, Amelie and V{\"o}gele, Daniel and Koss, Claus and Schlamp, Matthias and Dunnweber, Jan and Steffens, Oliver and Heckner, Markus and Jaritz, Sabine and Schiegl, Thomas and Corsten, Sabine and Lauer, Norina and Guertler, Katherine and Koenig, Eric and Haug, Sonja and Huber, Dominik and Birkenmaier, Clemens and Krenkel, Lars and Wagner, Thomas and Justus, Xenia and Saßmannshausen, Sean Patrick and Kleine, Nadine and Weber, Karsten and Braun, Carina N. and Giacoppo, Giuliano and Heinrich, Michael and Just, Tobias and Schreck, Thomas and Schnabl, Andreas and Gilmore, Amador T{\´e}ran and Roeslin, Samuel and Schmid, Sandra and Wellnitz, Felix and Malz, Sebastian and Maurial, Andreas and Hauser, Florian and Mottok, J{\"u}rgen and Klettke, Meike and Scherzinger, Stefanie and St{\"o}rl, Uta and Heckner, Markus and Bazo, Alexander and Wolff, Christian and Kopper, Andreas and Westner, Markus and Pongratz, Christian and Ehrlich, Ingo and Briem, Ulrich and Hederer, Sebastian and Wagner, Marcus and Schillinger, Moritz and G{\"o}rlach, Julien and Hierl, Stefan and Siegl, Marco and Langer, Christoph and Hausladen, Matthias and Schreiner, Rupert and Haslbeck, Matthias and Kreuzer, Reinhard and Br{\"u}ckl, Oliver and Dawoud, Belal and Rabl, Hans-Peter and Gamisch, Bernd and Schmidt, Ottfried and Heberl, Michael and G{\"a}nsbauer, Bianca and Bick, Werner and Ellermeier, Andreas and Monkman, Gareth J. and Prem, Nina and Sindersberger, Dirk and Tschurtschenthaler, Karl and Aurbach, Maximilian and Dendorfer, Sebastian and Betz, Michael A. and Szecsey, Tamara and Mauerer, Wolfgang and Murr, Florian}, title = {Forschung 2018}, editor = {Baier, Wolfgang}, address = {Regensburg}, organization = {Ostbayerische Technische Hochschule Regensburg}, isbn = {978-3-9818209-5-9}, doi = {10.35096/othr/pub-1382}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:898-opus4-13826}, pages = {98}, subject = {Forschung}, language = {de} } @article{LaumerKargSchmidt, author = {Laumer, Tobias and Karg, Michael Cornelius Hermann and Schmidt, Michael}, title = {Laser Beam Melting of Multi-Material Components}, series = {Physics Procedia}, volume = {39}, journal = {Physics Procedia}, publisher = {Elsevier}, issn = {1875-3892}, doi = {10.1016/j.phpro.2012.10.068}, pages = {518 -- 525}, abstract = {First results regarding the realisation of multi-material components manufactured by Laser Beam Melting of polymers and metals are published. For realising composite structures from polymer powders by additive manufacturing, at first relevant material properties regarding compatibility have to be analysed. The paper shows the main requirements for compatibility between different materials and offers first results in form of a compatibility matrix of possible combinations for composite structures.For achieving gradient properties of additively manufactured metal parts by using composite materials the composition of alloying components in the powder and adapted process strategies are varied. As an alternative to atomizing pre-alloyed materials, mixtures of different powders are investigated.}, language = {en} } @inproceedings{LaumerKargSchmidt, author = {Laumer, Tobias and Karg, Michael Cornelius Hermann and Schmidt, Michael}, title = {Neue Prozessstrategien zur Herstellung von Multi- Material-Bauteilen und Gradientenwerkstoffen}, series = {Zukunft individuell gestalten : Industriekolloquium des Sonderforschungsbereichs 814 - Additive Fertigung ; [Dezember 2012 ; N{\"u}rnberg]}, booktitle = {Zukunft individuell gestalten : Industriekolloquium des Sonderforschungsbereichs 814 - Additive Fertigung ; [Dezember 2012 ; N{\"u}rnberg]}, address = {Erlangen}, pages = {101 -- 116}, abstract = {Das additive Fertigungsverfahren, dem gemeinhin die gr{\"o}ßten Potentiale zugesprochen werden, ist das Laserstrahlschmelzen im Pulverbett von Kunststoffen (LSS-K) und von Metallen (LSS-M). Wie bei anderen Techniken der additiven Fertigung werden Bauteile direkt aus CAD-Dateien ohne zus{\"a}tzliche Werkzeuge bei enormer konstruktiver Freiheit gefertigt. Die resultierenden Werkstoffeigenschaften sind vergleichbar mit konventionelleren Prozessrouten wie etwa dem Spritzgießen thermoplastischer Polymere beziehungsweise auf der Seite der Metalle dem Schmieden oder Gießen. Derzeit wird der Einsatz des LSS zur Fertigung von Endprodukten in kleinen St{\"u}ckzahlen erschwert von nicht ausreichender Prozessstabilit{\"a}t und, insbesondere bei Kunststoffen, von der eingeschr{\"a}nkten Werkstoffauswahl. Bisher werden f{\"u}r beide Werkstoffklassen Bauteile aus jeweils einem einzigen Ausgangsmaterial hergestellt. N{\"a}herungsweise erzeugt LSS also einheitliche Materialeigenschaften {\"u}ber das gesamte Bauteil hinweg. Ein Ansatz, der in den Teilprojekten A5 und B6 des Sonderforschungsbereichs 814 verfolgt wird, ist die Realisierung von Multi-Material-Bauteilen mittels LSS-K beziehungsweise LSS-M.}, language = {de} } @inproceedings{LaumerKargSchmidt, author = {Laumer, Tobias and Karg, Michael Cornelius Hermann and Schmidt, Michael}, title = {Additive Manufacturing of Gradient and Multimaterial Components}, series = {International Conference on Competitive Manufacturing COMA, 2013, Stellenbosch}, booktitle = {International Conference on Competitive Manufacturing COMA, 2013, Stellenbosch}, abstract = {In the paper first results regarding the realisation of gradient and multi-material parts manufactured by Laser Beam Melting in powder bed of metals and polymers are published. Gradient properties of additively manufactured metal parts can be achieved by varying the composition of alloying components in the powder and adapting process strategies. As an alternative to atomizing pre-alloyed materials, mixtures of different powders are investigated. For realizing multi-material-parts from polymers, at first relevant material properties concerning compatibility have to be analysed. Therefore the paper shows the main requirements for compatibility between different materials and also first results regarding the compatibility of polymer powders and possible combinations for the manufacturing of multi-material components by laser beam melting of polymers.}, language = {en} } @inproceedings{LaumerKargSchmidt, author = {Laumer, Tobias and Karg, Michael Cornelius Hermann and Schmidt, Michael}, title = {Neue Prozessstrategien zur Herstellung von Multi-Material-Bauteilen mit Hilfe des Laserstrahlschmelzens}, series = {Industriekolloquium des SFB 814, 2, 2013, N{\"u}rnberg}, booktitle = {Industriekolloquium des SFB 814, 2, 2013, N{\"u}rnberg}, publisher = {Universit{\"a}t Erlangen-N{\"u}rnberg, Lehrstuhl f{\"u}r Kunststofftechnik}, isbn = {978-3-931864-59-0}, language = {de} } @inproceedings{LaumerSchmidtStichel, author = {Laumer, Tobias and Schmidt, Michael and Stichel, Thomas}, title = {Influence of temperature gradients on the part properties for the simultaneous laser beam melting of polymers}, series = {Proceedings of Laser in Manfacturing Conference 2015, June 22 - June 25, 2015 Munich, Germany}, booktitle = {Proceedings of Laser in Manfacturing Conference 2015, June 22 - June 25, 2015 Munich, Germany}, organization = {German Scientific Laser Society (WLT e.V.)}, abstract = {By Laser Beam Melting of polymers (LBM), parts with almost any geometry can be built directly out of CAD files without the need for additional tools. Thus, prototypes or parts in small series production can be generated within short times. Up to now, no multi-material parts have been built by LBM, which is a major limitation of the technology. To realize multi-material parts, new mechanisms for depositing different polymer powders as well as a new irradiation strategy are needed, by which polymers with different melting temperatures can be warmed to their specific preheating temperatures and be molten simultaneously. This is achieved by simultaneous laser beam melting (SLBM). In the process, two different materials are deposited next to each other and preheated a few degrees below their melting temperatures by infrared emitters and laser radiation (λ = 10.60 µm), before in the last step the two preheated powders are molten simultaneously by an additional laser (λ = 1.94 µm). So far, multi-material tensile bars have been realized and analyzed regarding their boundary zone between both materials. The experiments showed that the temperature gradients in the boundary zone and along the building direction seem to be of great importance for the process stability and the resulting part properties. Therefore, a detailed analysis of the occurring temperature gradients during the process is needed to identify adequate process adjustments regarding the temperature controlling. To analyze the temperature gradients, thermocouples positioned inside the powder bed are used. By varying the temperature of the building platform, the influence of different temperature gradients on the resulting part properties is shown.}, language = {en} } @article{LaumerStichelRiedlbaueretal., author = {Laumer, Tobias and Stichel, Thomas and Riedlbauer, Daniel and Amend, Philipp and Mergheim, Julia and Schmidt, Michael}, title = {Realization of multi-material polymer parts by simultaneous laser beam melting}, series = {Journal of Laser Micro / Nanoengineering}, volume = {10}, journal = {Journal of Laser Micro / Nanoengineering}, number = {2}, publisher = {Japan Laser Processing Society}, abstract = {In this paper, first results regarding the realization of multi-material parts by Simultaneous Laser Beam Melting (SLBM) of polymers are presented. This new approach allows the layerwise generation of parts consisting of different polymer materials within one building process. Besides the typical advantages of additive manufacturing technologies, such parts can fulfill different product requirements concomitant and therefore could enlarge the overall field of application. The powder materials used for this paper are polyethylene (PE) and a polyamide based thermoplastic elastomer (TPE). After depositing the powder materials next to each other, infrared-emitters heat the lower melting polymer and a CO2 laser provides the preheating temperature of the higher melting polymer. In the last step, a thulium fibre laser melts the two preheated powders simultaneously. The realized specimens are characterized by cross sections and their tensile strengths are determined. Additionally, the new approach of the simultaneous energy irradiation is investigated using a Finite Element Analysis in order to gain a more profound process understanding. In that sense, the influence of the size of the exposure area on the reachable maximum temperatures inside that area was analyzed by the simulation and compared to experimental studies.}, language = {en} }